1. Field of the Invention
The present invention relates to a system that assists in the performance of a surgical procedure by generating images to illustrate the relative position of various body parts and instruments during the surgical procedure, and, more particularly, to an image guided system that employs a position tracking device that is adjustably mounted to an instrument.
2. Description of the Related Art
In recent years, a variety of different types of surgical navigation systems have been introduced in order to improve the performance of surgical procedures. For instance, U.S. Pat. Nos. 5,383,454; 5,851,183; 5,871,445; and 5,891,034 to Bucholz; PCT Application No. PCT/US94/04530 (Publication No. WO 94/24933) to Bucholz; and PCT Application No. PCT/US95/12894 (Publication No. WO 95/11624) to Bucholz et al., the entire disclosures of each of which is incorporated herein by reference, disclose surgical navigation systems that illustrate the position of medical instruments during surgical procedures.
A typical navigation system employs a scanner to generate images for indicating the position of a medical instrument relative to a predetermined body part, for example. Moreover, such surgical navigation systems typically include position tracking devices, such as for example, a position indicating LED and/or reflector array arranged about a body part as well as position indicating LEDs and/or reflectors mounted on a medical instrument, which are part of a position sensing device further including a digitizer camera to track the positions of the selected body parts and medical instruments, and a display for illustrating the relative positions of the body party and the medical instrument during the medical procedure.
Although these types of systems can be effective, additional improvements are desirable to facilitate the mating of medical instruments to position tracking devices. For example, accurate illustration of the precise position of a medical instrument is of paramount importance in virtually any image guided medical procedure. This is true because a primary purpose of utilizing a navigation system is to allow an operator to perceive accurately the precise location of a body part relative to the location of the medical instrument being implemented. If a medical instrument is not adequately mounted to the position tracking device, then the navigation system may lose information about the precise location of the medical instrument relative to the position tracking device. Consequently, an inaccurate illustration of the location of the medical instrument relative to a body part may result.
With this in mind, typical surgical navigation systems employing known mounting devices can suffer from several important drawbacks. In conventional navigation systems, for example, rigid clamping brackets, e.g., in the form of a "C" clamp, and associated clamping screws may be used to attach medical instruments to respective position tracking devices. As such, the amount of frictional clamping force available in such conventional clamping bracket designs may be inherently limited. This is so because the contact area between conventional brackets and medical instruments is restricted to a point or along a line. Thus, conventional bracket mechanisms may increase the likelihood that an inaccurate illustration of the position of a medical instrument will occur, as discussed above, because the stability of conventional position tracking mounting devices may be compromised.
As another example, known position tracking mounting devices are not capable of satisfactorily accommodating a wide variety of medical instrument shapes and sizes. Indeed, known clamping devices may need to be replaced each time a medical instrument having a different shape and/or size is desired. In particular, known mounting designs contemplate the use of custom made position tracking mounting mechanisms for medical instruments that are of a different size or shape. Moreover, when using a plurality of different instruments in a single surgical procedure, known position tracking mounting arrangements can fail to facilitate efficient replacement of a variety of medical instruments having different sizes and shapes. As a result, known position tracking mounting devices require unnecessary time, expense and inconvenience.
Additionally, conventional surgical navigation systems employ position tracking mounting devices that can fail to adequately address the hazards of introducing new medical instruments into a surgical field prior to and/or during a surgical procedure. Namely, if a new medical instrument is introduced into a surgical procedure without re-calibrating the position of the newly introduced instrument relative to a known reference point, then inaccurate illustration of the position of the medical instrument on the display can result as discussed above. Accordingly, a simple and reliable way to require an operator to properly re-calibrate and/or re-register the position of a newly introduced medical instrument is desirable.
As a further example, typical surgical navigation systems employ known position tracking devices that are not always adjustably mounted in a stable manner to a medical instrument in a variety of geometric configurations. Adjustably mounting a medical instrument to a position tracking device is advantageous for a number of important reasons. For instance, a clear line of sight between the digitizer camera and the emitters and/or reflectors of the position tracking should be maintained throughout the medical procedure, itself. If this line of sight is interrupted, then inaccurate illustration of the position of the medical instrument can result, as discussed above. In practice, it is advantageous for a surgeon to be able to position the medical instrument in a particular orientation. In order to position the medical instrument as such, the emitters and/or reflectors of the conventional position tracking device may be forced to point away from the digitizer camera. However, if the position tracking device is adjustably mounted relative to the medical instrument in a stable manner, then the emitters and/or reflectors can be controlled to be continuously directed toward the digitizer camera while the medical instrument is placed in a particular orientation.
In light of the foregoing, there are a need for an improved image guided universal attachment device in surgical navigation systems.